Digital vibration coupling stud

ABSTRACT

A vibration coupling stud for use in a vibration monitoring system includes digital memory and temperature sensing devices. Data is transferred between the vibration coupling stud and a vibration monitor. Data stored in the stud may include asset identification code, measuring point identification, prior measurement data, machine or bearing part numbers, and alarm limits.

RELATED APPLICATIONS

[0001] This application contains subject matter related to U.S.application Ser. No. 08/898,485 and Ser. No. 09/178,068, both of whichare entitled “Digital Vibration Coupling Stud,” and which were filed onJul. 22, 1997 and Oct. 23, 1998 respectively. The disclosures ofapplication Ser. No. 08/898,485 and Ser. No. 09/178,068 are herebyincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

[0002] I. Field of the Invention

[0003] The present invention relates to apparatus for the detection ofbearing and other malfunctions in machinery. More specifically, thepresent invention relates to portable vibration monitors and vibrationcoupling studs for monitoring the vibrational and other characteristicsof the machine.

[0004] II. Description of the Related Art

[0005] In order to properly maintain machinery used in manufacturingfacilities, power generating stations, etc., it has become common toemploy vibration monitoring equipment to detect variations in thevibration characteristics of the machinery while they are operating.This assists in the determination of appropriate intervals for machinemaintenance, and as a warning of imminent machine failure. It can beappreciated that proper scheduling of maintenance can improve theoperating efficiency of the facility, and that a warning of imminentmachine failure can avoid catastrophic machine damage as well as dangerto facility personnel.

[0006] Many systems have been developed to implement such a monitoringprocedure. In some systems, as described in U.S. Pat. No. 5,430,663 toJudd et al., for example, transducers are fixed to machinery throughouta plant or other facility, and the electrical signals from thetransducers are wired to a central computer system for monitoring.Another system of this nature is described in U.S. Pat. No. 5,191,327 toTalmadge et al. In the system described by Talmadge, the analogtransducer signal is pre-processed with programmable filtering circuitrylocated within the transducer housing. The central computer of theTalmadge et al. system can both store and retrieve transducer ID dataand instructions directing signal pre-processing into and out of amemory located within-the transducer housing at the measuring point.

[0007] Systems of this design have the advantage that all points ofinterest in the plant can be continuously and simultaneously monitored.However, such a system is expensive to implement, requiring a largenumber of dedicated vibration transducers as well as interconnectingwiring strung throughout the facility. Accordingly, such implementationsare most useful in situations where machine failure may have especiallyserious consequences, such as in a nuclear power plant for example.

[0008] A less expensive alternative to such a system uses a portablemonitoring probe having an internal transducer and signal processingcircuitry. A system such as this is described in U.S. Pat. No. 4,520,674to Canada et al. In systems of this design, plant personnel will walk agenerally predetermined route around a facility being monitored in orderto apply a portable data collection device to measuring points atvarious locations on the machinery to be monitored. In the Canada et al.patent, for example, a technician carries a handheld probe which isconnected to a separate portable data collection and processing device.One portion of the handheld probe is placed either in direct contactwith the outside of the machine to be monitored, or in direct contactwith a vibration coupling stud secured to the outside of the machine tobe monitored. Mechanical vibration is thus coupled to an internalpiezoelectric vibration transducer for creating an electrical signalindicative of the vibratory acceleration of the machine being monitored.The handheld probe then outputs an analog vibration signal to a separatedata collection and processing device. Vibration parameters such asacceleration and velocity are calculated and stored for later analysis.

[0009] A commercially available device of this nature is the Picolog(TM) from SKF Condition Monitoring of San Diego, Calif. The Picologsystem comprises a handheld probe capable of measuring and storinghundreds of separate vibration level measurements. These measurementsare later uploaded to a host computer system for analysis. The Picolog(TM), however, does not provide a real-time output of the vibrationmeasurement.

[0010] Although these systems are relatively inexpensive, they haveseveral disadvantages. One fundamental disadvantage is that thetechnician must accurately record where and when each vibrationmeasurement is taken. Although a specific route which is followed by alltechnicians when gathering vibration data may be established, but thisincreases the required training, and some transcriptional or other routeerrors are essentially inevitable.

[0011] Although some devices have been designed to alleviate thisproblem, significant potential for improvement remains. A systemdescribed in U.S. Pat. No. 4,800,512 to Busch discloses a vibration datameasuring probe which can read a measuring point code from a vibrationcoupling stud located at a particular measuring point. The coupling studof this system includes a unique identifier such as a bar code, aspecific arrangement of magnets, a ridge pattern, or other similaridentifying characteristic. When the portable probe is applied to thecoupling stud, a reader slides along the bar code, magnets, ridges,etc., thereby creating a signal which is transferred to a computerattached to the probe. This system is stated to allow the computer toidentify the coupling stud the probe is attached to, thereby reducing oreliminating the need to manually transcribe information regarding thedata point. However, the amount of information storable in the vibrationcoupling stud is very limited, and the probe required to read the codeis mechanically complex.

[0012] What is needed in the art is therefore a vibration datacollection system which incorporates increased capabilities for datastorage at the measuring point, which is easy to use, and which isinexpensive to manufacture.

SUMMARY OF THE INVENTION

[0013] A stud for coupling machine vibrations to a transducer storesdata in a memory. The data may include an asset identification codeidentifying the asset to which the stud is attached.

[0014] In one embodiment, the stud comprises a body having a machineattachment portion for attaching the stud to a point on a machine andone or more memories mounted on the stud. The memories store one or moretypes of data selected from the group consisting of asset identificationcode, alarm limits, bearing part number, bearing qualitycharacteristics, lubrication information, installation date, signalfiltering parameters, defect indication frequency, and date stampedvalue of a parameter measured during a previous data collectionoperation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a perspective view of a portable vibration monitoringsystem in accordance with a preferred embodiment of the presentinvention.

[0016]FIG. 2A is side view of the handheld portion of the portablevibration monitoring system of FIG. 1.

[0017]FIG. 2B is a top view of the handheld monitor of FIG. 2A.

[0018]FIG. 2C is a rear view of the handheld monitor of FIG. 2A.

[0019]FIG. 2D is a front view of the handheld monitor of FIG. 2A.

[0020]FIG. 3 is a block diagram of a portion of the internal circuitryof the handheld vibration monitor of FIG. 2A.

[0021]FIG. 4 is a cutaway side view of the handheld probe of FIG. 2A,illustrating the transducer and contact portions of the handheldvibration monitor.

[0022]FIG. 5 is a cutaway side view of an alternative embodiment of ahandheld vibration monitor.

[0023]FIG. 6A is a cutaway side view of an alternative embodiment of ahandheld vibration monitor.

[0024]FIG. 6B is a front view of the monitor probe of FIG. 6A.

[0025]FIG. 7A is a cutaway side view of an alternative embodiment of ahandheld vibration monitor.

[0026]FIG. 7B is a front view of the monitor probe of FIG. 7A.

[0027]FIG. 8A is an exploded view of one embodiment of a vibrationcoupling stud in accordance with one aspect of the present invention.

[0028]FIG. 8B is a perspective view of a printed circuit board adaptedfor installation in a vibration coupling stud.

[0029]FIG. 9A is a top view of the printed circuit board of FIG. 8B.

[0030]FIG. 9B is a bottom view of the printed circuit board of FIG. 8B.

[0031]FIG. 10 is a top view of the vibration coupling stud of FIG. 8Bwith the printed circuit board installed.

[0032]FIG. 11 is a cutaway side view along line 11-11 of the vibrationcoupling stud of FIG. 10.

[0033]FIG. 12 is a second cutaway side view along lines 12-12 of thevibration coupling stud of FIG. 10.

[0034]FIG. 13 is a cutaway side view along lines 13-13 of the handheldvibration monitor of FIG. 2 when interfaced with the vibration couplingstud of FIG. 10.

[0035]FIG. 14A is a cutaway side view of an alternative embodiment of avibration coupling stud.

[0036]FIG. 14B is a top view of the vibration coupling stud of FIG. 14A.

[0037]FIG. 15 is an exploded view of another embodiment of a vibrationcoupling stud.

[0038]FIG. 16A is a cutaway side view of the vibration coupling stud ofFIG. 15 after assembly.

[0039]FIG. 16B is a top view of the vibration coupling stud of FIG. 16A.

[0040]FIG. 17 is a cutaway side view of the handheld vibration monitorof FIGS. 7A and 7B when interfaced with the vibration coupling stud ofFIGS. 16A and 16B.

[0041]FIG. 18 is a flowchart of operational steps performed by avibration monitoring system according to one embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0042] Preferred embodiments of the present invention will now bedescribed with reference to the accompanying Figures, wherein likenumerals refer to like elements throughout. The terminology used in thedescription presented herein is intended to be interpreted in itsbroadest reasonable manner, even though it is being utilized inconjunction with a detailed description of certain specific preferredembodiments of the present invention. This is further emphasized belowwith respect to some particular terms used herein. Any terminologyintended to be interpreted by the reader in any restricted manner willbe overtly and specifically defined as such in this specification.

[0043]FIG. 1 illustrates major components of one embodiment of thepresent invention as well as illustrating its most common environment ofuse. Accordingly, FIG. 1 shows a portion of a machine which incorporatesa rotating shaft 12 mounted inside a ball bearing, journal bearing, orthe like. The bearing may be mounted in a bearing housing 10. Therotating components of the machine, such as the shaft 12 mentionedabove, produce characteristic vibrations of the bearing housing 10 andthe machine as a whole which are communicated to a vibration couplingstud 14 which is secured to the bearing housing 10 or the machineenclosure, typically with a threaded connection into the machineenclosure or into the bearing housing 10 which is part of the overallmachine.

[0044] It will be appreciated that the machine may be any type ofvibrating device, including a turbine, pump, fan, or the like. Asmentioned above, the vibration coupling stud 14 may be secured to amachine enclosure or other integral part, thereby coupling vibrations ofan entire machine to a vibration monitoring system. Alternatively, insome embodiments of the present invention, one or more vibrationcoupling studs 14 are secured to a housing 10 for an individual bearingso that the vibration characteristics of shaft rotation within thesingle bearing may be examined and individual bearing conditiontherefore monitored as well. In these and similar cases, an individualbearing may be considered a portion of a machine, or may itself beconsidered a machine which is being monitored. The use of the word“machine” in this disclosure is thus intended to cover any device forwhich condition monitoring is advantageous, and is not intended to belimited to specific locations or specific types of apparatus.

[0045] The vibration coupling stud 14 provides a location which isadapted to accept a probe 23 with an end extending from a portablevibration monitor 20, which is illustrated in FIG. 1 as being compactenough to be handheld, although this is not required for portability. Ascan be seen in FIG. 1, a portion of the probe 23 is external to thehousing 21 of the handheld vibration monitor 20. As will also bediscussed below with reference to FIGS. 7 and 10, the probe 23 maycomprise opposed flat sides 17, 18 and opposed threaded surfaces 25, 27to allow for the establishment of a consistent mechanical couplingbetween the probe and the stud 14 via a {fraction (1/4)} turn threadedengagement. As will be seen below with reference to FIGS. 4 through 6, avariety of different connection formats are possible, although certainconfigurations have characteristics which are especially desirable.

[0046] In the embodiment of FIG. 1, the handheld vibration monitor 20includes a vibration transducer (illustrated in the partial cutaway viewof FIG. 4), typically a piezoelectric crystal, which is in mechanicalcontact with a portion of the probe 23 inside the housing 21 of thehandheld vibration monitor 20. When the probe 23 is held in contact withthe vibration coupling stud 14, the vibration is mechanicallytransferred to the transducer inside the housing 21 to produce anelectrical signal for analysis. As will be described below, a portion ofthis analysis may be performed within the handheld vibration monitor 20,and additional analysis may be performed on a device external to thevibration monitor 20, such as an associated palm-top data processor orcomputer 22, which communicates with the handheld vibration monitor 20over a communication link 24. The handheld vibration monitor 20additionally may comprise a display 26, and a keypad 28 for direct userinterface and control. It may be noted that in some embodiments of thevibration monitoring system herein described the palm-top data processor22 may or may not be used with the handheld vibration monitor 20. As astand-alone device, the handheld vibration monitor 20 may be configuredto at least perform the data analysis necessary to compare the receivedvibration signal with alarm limits. When the palm-top computer isprovided, data transfer between the palm-top computer 22 and thehandheld vibration monitor 20 can occur as will be described below, andmore sophisticated data storage and analysis can be performed.

[0047] In some advantageous embodiments which include the palm-topcomputer 22, signal processing performed inside the handheld vibrationmonitor 20 produces vibration data of various types in digital form.This digital data can then be communicated to the palm-top computer 22using established communication protocols such as RS-232, RS-422, etc.which are well known to those of skill in the art, and whichcommercially available palm top computers are already adapted to receiveand transmit. Although illustrated as a physical cable in FIG. 1, itwill be appreciated that the communication link 24 may also utilizewireless methods such as infrared or RF based communication links. Thepalm-top data processor 22 may comprise a standard portable computingdevice available from several sources. The palm-top data processor may,for example, be a DOS or Windows (TM) based personal computer, and mayadvantageously include a keypad and/or a pen based user interface. Inaccordance with the above, the palm-top computer also preferablyincorporates an RS-232 or other standard I/O interface for communicatingwith the handheld vibration monitor 20. With this configuration, nospecialized communication hardware needs to be incorporated into thepalm-top computer 22, and a large variety of currently availableindustry standard computers may be appropriately programmed to functionas the palm-top computer 22 of the present vibration monitoring system.

[0048] The palm-top computer 22 is also preferably suitable for use inindustrial environments involving rough handling, and possibly even thepresence of explosive gases. Palm-top computers which are suitable foruse in the system of FIG. 1 are commercially available, for example, asthe PPT 4600 Series from Symbol Technologies of Holtsville, N.Y.

[0049] In FIGS. 2a through 2 d, several views of an advantageoushandheld vibration monitor 20 are presented. Referring now to FIGS. 2aand 2 b, the handheld vibration monitor 20 is shown in side view and topview respectively, illustrating the display 26 and keypad 28 on thehousing 21 in FIG. 2a. In addition to the display, which advantageouslycomprises an LCD display, several different color alarm LEDs 27 may alsobe provided. The keypad 28 may include three separate function keys. Onekey 30, preferably comprises an “ON/OFF” key for unit activation. Asecond “BACKLIGHT” key 32 turns a display backlight on and off. A“DISPLAY” key 34 allows the user to scroll through several alternatedisplays, such as a display of the value currently being measured, adisplay of current alarm setpoints, or a display of current dangersetpoints.

[0050] In some embodiments of the present invention, two “TAKE DATA”buttons 36, 38 are provided on the housing. The two “TAKE DATA” keys maybe provided on opposite surfaces of the housing 21 at the same locationalong the length of the handheld vibration monitor 20. Both of thesebuttons have identical functionality. As will be explained below in moredetail in conjunction with FIG. 14, actuation of either “TAKE DATA” keywill initiate the processing of the electrical signal produced by theinternal transducer. Measured vibration signal characteristics such asvelocity, acceleration, enveloped acceleration, or other calculatedvibration measurement values can then be presented on the display oroutput to the palm-top computer 22.

[0051] The housing 21 may be formed to comprise an outward bulge 40extending along the side opposite the display 26. With this housing 21shape and “TAKE DATA” key 36, 38 placement, a user may hold thevibration monitor 20 in either the left or right hand, and with thebulge 40 resting in the palm of the hand, the user's left or right thumbrests comfortably over one or the other “TAKE DATA” key 36, 38.

[0052] As is illustrated in the rear view of FIG. 2c, the handheldvibration monitor 20 may also comprise a communication port 42 forinterfacing with the palm-top computer 22 described above. In theembodiment illustrated in FIG. 2, the communication port comprises a 9pin D-subminiature connector well known to those of skill in the art andwhich is often used in the standard serial RS-232 digital datacommunication protocol.

[0053]FIG. 3 shows a block diagram of the processing circuitry insideone embodiment of the handheld vibration monitor 20, as well as themechanical and electrical interface between the stud 14 and the monitor20. The central component is a microprocessor 66 which controls themonitor 20 function and performs some or all of the data processing onthe vibration signal received from the machine being monitored. Thecircuitry includes a function key interface 68, and an I/O interface 70for communication with an external data processor such as the palm-topcomputer 22 discussed above. Display driver circuitry 72 and memory 74are also coupled to the microprocessor 66, either via two separate busesor, as shown in FIG. 4, via a shared bus. The memory 74 is preferably atleast partially non-volatile, and stores information such as alarmlimits, and the current date and time. Also preferably stored in thememory is a bearing severity matrix which comprises a table correlatinga list of bearing types, a code for particular bearing or machineconfigurations, unique measuring point identifiers, or otheridentification data with appropriate alarm and danger vibration levels.With a stored matrix of this sort, a given numerical vibrationmeasurement may produce a different alarm status depending on the pointat which the measurement is taken. Also important is the stud interface80, which provides electrical and mechanical communication between thestud 14 and the monitor 20.

[0054] The microprocessor receives signals from the stud 14 via twodifferent routes. The first is via a mechanical coupling 76 between thestud 14 and the transducer 52 which is mediated by the mechanicalcoupling features of the stud interface 80. The output of the transducermay be filtered by analog anti-aliasing or other filters and is thensampled and digitized by an analog to digital converter 78 to produce aseries of digital samples defined by the analog output of thetransducer. The analog to digital converter 78 transmits the samples tothe microprocessor 66 for calculations of acceleration or velocityamplitudes, as well as other characteristics of the vibration signalfrom the machine being monitored. Specific vibrational signaturesindicative of bearing wear or malfunction, such as envelopedacceleration measurements, can also be observed and their presenceand/or degree can be communicated to the user either with the display 26or via the communication link to the palm-top computer 22. In someadvantageous embodiments, the microprocessor 66 calculates a discretefrequency spectrum of the incoming digital samples. The results of thiscalculation can be used to calculate various vibrational parametersinside the monitor 20, or they may be communicated to the palm-topcomputer 22 for analysis. If desired, sampled values output from theanalog to digital converter 78 can be transmitted to the palm-topcomputer 22 in real time as the vibration measurement is being made.

[0055] The stud interface 80 also forms an electrical coupling 77between the processor 66 with memory and/or other circuitry embedded inthe stud 14. As will be seen below, the design of this electricalcoupling is advantageously as illustrated in one of the embodimentsillustrated in FIGS. 4-13. Through this interface 80, the handheldvibration monitor 20 can retrieve data stored in such stud mountedmemory ICs. This data may include bearing type, measuring pointidentification, a code indicating bearing configuration, known bearingdefect frequencies, a baseline vibration reading, previously takenvibration measurements along with the time and/or date the measurementwas taken, stored alarm limits, as well as other types of data describedmore fully below with reference to the stud 14 itself. Also, when usedwith an appropriately configured vibration coupling stud 14, thehandheld vibration monitor 20 can transmit data via the stud interface80 to the vibration coupling stud 14, such as measured vibrationcharacteristics, revised alarm limits, a severity matrix relevant to themeasuring point, etc.

[0056] Referring now to FIG. 4, a cutaway view of one embodiment of thehandheld vibration monitor 20 is shown. Held in place between two halves21 a, 21 b of the monitor housing 21 is the probe 23. In thisembodiment, the probe 23 comprises a body which may advantageouslyinclude a rounded tip 48 at an end extending out from the housing 21.This tip 48 makes physical contact with a portion of the vibrationcoupling stud 14 to couple mechanical vibrations from the machine to thehandheld vibration monitor 20. The probe 23 may also comprise a{fraction (1/4)} turn threaded portion 50 (also illustrated in FIGS. 2Aand 2B, and comprising threaded sections 25 and 27 illustrated inFIG. 1) intermediate between the tip 48 and the probe 23 entry pointinto the housing 21. The threaded portion 50 is preferably configured tomate with a threaded portion of the vibration coupling stud 14, as willbe explained in detail below with reference to FIG. 12. The threadedsection 50 also preferably is of a double-start configuration, such thatthe threaded surfaces 25, 27 engage identically with the stud, whichresults in a {fraction (1/4)} turn engagement regardless of the initialorientation of the probe 23 when it is placed in contact with the stud14.

[0057] Inside the housing 21, the other end of the probe 23 ismechanically coupled to the vibration transducer 52. As is known in theart, the vibration transducer 52 may be a compression, annular shear, orother suitable style. The most appropriate type of transducer 52 willdepend on the desired frequency response, sensitivity, and otherparameters which may vary with intended operating environment. Those ofskill in the art will be readily capable of selecting a transducersuitable for use in the handheld monitor described herein. It is mostadvantageous, of course, for the probe 23 to be tightly mechanicallycoupled to the transducer 52, and mechanically isolated from the housing21 itself. Suitable methods of accomplishing these objectives will alsobe apparent to those of skill in the art.

[0058] Two electrical contacts to the transducer 52 are made, one ofwhich comprises a circuit common 53 which is electrically tied to themetal probe 23 body. A second, signal electrical contact 54 is also madewith the transducer 52 in a conventional manner. Both of theseconnections are connected to leads which route the analog electricalsignal produced by the transducer 52 to the internal processingcircuitry.

[0059] As shown in FIG. 3, the stud interface 80 also includes anelectrical coupling 77 between the stud 14 and the monitor 20. Onealternative configuration of this electrical coupling 77 is illustratedin FIG. 4. Thus, some embodiments of the present invention include asleeve 56 made of a dielectric plastic material surrounding the probe 23body. This dielectric sleeve 56 may in turn be surrounded by aconductive metal sleeve 58 which extends outside the housing 21 to apoint short of the top of the threaded portion 50, thus creating anotherconductive contact near the probe. Internal to the housing 21, anelectrical contact 60 is made to the outer sleeve 58. Thus, a coaxialtype electrical structure may be created by the central probe 23 body,dielectric sleeve 56, and outer sleeve 58. This coaxial structureincludes the circuit common 53 comprising the probe 23 body as describedabove and a second signal lead 62 internal to the housing 21, which isalso routed to the processing circuitry inside the monitor 20. As willbe explained further below, the above described structure is adapted toelectrically connect circuitry internal to the handheld vibrationmonitor 20 with an electrical contact on the vibration coupling stud 14so as to transfer data between the handheld vibration monitor 20 andintegrated circuits (ICs) mounted in the vibration coupling stud.

[0060] Although a coaxial type structure is illustrated in FIG. 4, othermethods of creating an electrical contact near the probe 23 tip arepossible. For example, in one alternative embodiment illustrated in FIG.5, the portion of the probe above the threaded section 50 is surroundedby a dielectric sleeve 57 which is provided with a metal ring 59 moldedinto the lower end of the dielectric sleeve, and having an exposedsurface which forms the desired conductive contact. In this embodiment,a hole 61 may be provided longitudinally through the body of the sleeveso as to extend from inside the housing of the handheld vibrationmonitor to the top portion of the metal ring. A wire may be threadedthrough this longitudinal hole to connect to the metal ring 59 and whichforms the signal connection 62.

[0061] Additional alternatives for creating the electrical portion ofthe stud interface 80 are illustrated in FIGS. 6A, 6B, 7A and 7B. Inthese embodiments, the probe 23 a is formed so as to comprise a threadedreceptacle 47, rather than as a plug as shown in FIGS. 1-5 As is bestillustrated in the front views of FIGS. 6B and 7B, the receptacle 47 mayhave an oblong cross section similar to that shown for the plug styleprobe 23 of FIGS. 1 and 2A-2D. In this case, the stud 14 may comprisethe mating plug portion, configured in a manner analogous to the probe23 previously described, as is discussed below with reference to FIGS.14A, 14B, 15A, and 15B. The rear end of the probe 23a forms a mount forthe vibration transducer 52.

[0062] As with the embodiments of FIGS. 4 and 5, the metal body of theprobe 23 a forms the ground connection 53 between the stud 14 and thevibration monitor 20. In the embodiment of FIGS. 6A and 6B, the signalconnection is established by securing a printed circuit board 49 insidethe receptacle 47 with epoxy adhesive or other mechanical fasteningmeans. Soldered to the printed circuit board 49 is a resilient metaldome 51. Through a longitudinal hole in the probe 23 a, the signal lead62 that extends to the processing circuitry inside the monitor 20 iselectrically connected to the dome 51, thus forming another electricalcontact proximate to the probe 23 body. As will be explained furtherbelow, the dome 51 makes contact with a conductive pad or trace on aprinted circuit board in an appropriately configured stud 14, such asthe design illustrated in FIGS. 14A and 14B, to communicate with memoryand/or other circuitry embedded in the stud 14.

[0063] In the embodiment illustrated in FIGS. 7A and 7B, a resilientdome is not used. This embodiment is thus adapted to most advantageouslyinterface with a stud that includes a resilient contact, as will bediscussed in further detail below with reference to FIGS. 15, 16A and16B. In this embodiment, an insulator 64 is affixed to the bottom of thereceptacle 47, and a solid conductive contact 65 is secured to theinsulator 64. The signal lead 62 may be threaded through a hole in theinsulator 64 to electrically connect to the contact 65.

[0064] One embodiment of a vibration coupling stud 14, which isespecially adapted for use with the handheld vibration monitor 20 ofFIGS. 1 through 5 is shown in FIGS. 8A and 8B. As is illustrated in theexploded view of FIG. 8A, one embodiment of an advantageous vibrationcoupling stud 14 includes a metal body comprising an upper hex-nutportion 84 and a lower threaded portion 86 extending therefrom along acentral longitudinal axis 85 of the body of the stud 14. The lowerthreaded portion 86 is threadably installed into a beating housing ormachine enclosure, thereby attaching the stud to a machine measuringpoint when the stud is to be used as part of a vibration monitoringsystem. The vibration coupling stud may also include a rubber or plasticcover 88 for covering the stud 14 body when measurements are not beingtaken.

[0065] Preferably, the top surface 90 of the upper hex-nut portion ofthe vibration coupling stud 14 is machined to incorporate a recess 92which is configured to mount a printed circuit board 94. To properlymate with the printed circuit board 94 and its components, the bottom ofthe recess 92 includes a plurality of cavities. One such cavity maycomprise a centrally located probe receptacle 96. The probe receptacle96 extends generally along the longitudinal axis 85 from the bottomsurface of the recess 92 into the body of the stud 14. Opposed sides ofthe probe receptacle 96 are provided with threads 97 which engage withthe threaded surfaces 25, 27 of the probe 23. It can be appreciated withexamination of FIGS. 2 and 5A that the probe receptacle 96 is shaped toslidably accept the probe 23 with the flat surfaces 17, 18 of the probe23 aligned adjacent to the threaded surfaces 97 inside the probereceptacle 96. A {fraction (1/4)} turn of the vibration monitor 20(producing {fraction (1/4)} turn of the probe tip 23 as well) will thenengage the threads 25, 27 on the probe 23 with the threads 97 in theprobe receptacle 96. As will be described below in conjunction with FIG.10, this {fraction (1/4)} turn solidly mates the probe 23 with the probereceptacle 96 when vibration measurements are to be taken.

[0066] As has also been mentioned briefly above, one or more integratedcircuits (“ICs”) 104 are soldered to the printed circuit board 94. Insome embodiments, the ICs 104 are memory ICs for storing data concerningvibration measurements, alarm limits, bearing data, etc. In someadvantageous embodiments of the present invention, the memory ICs haveonly two electrically active terminals, one comprising a signalterminal, and one comprising a ground terminal. Memory ICs which aresuitable for use in some embodiments of the stud 14 of the presentinvention are commercially available, for example, as part numberDS2430A from Dallas Semiconductor of Dallas, Tex. These devices include256 bits of EEPROM memory which is serially written to and read fromover the one signal terminal provided. These devices also include a 48bit serial number so that individual memory ICs can be connected inparallel to a single signal line and addressed separately by an externaldevice.

[0067] Furthermore, in other embodiments of the vibration coupling stud14, one of the ICs soldered to the printed circuit board 94 may alsocomprise a electronic temperature sensor which has a digital outputindicative of the temperature of the device. Preferably, the digitaloutput is available serially over a single signal lead in a manneranalogous to that described above with respect to the memory IC.Suitable temperature sensors of this nature are also commerciallyavailable from, for example, Dallas Semiconductor as part number DS1820.Additional types of transducers may also be incorporated into the stud.For example, vibration, current, flow, pressure, or speed sensors may beprovided in addition to or as alternatives to the memory and temperaturedevices specifically described above.

[0068] As is illustrated in FIG. 8A, several tapped holes 98 foraccepting printed circuit board mounting hardware 100 are also providedin the bottom of the recess 92, and the printed circuit board 94 isinstalled in the recess 92 in what would usually be considered upsidedown, with the ICs extending away from the printed circuit board 94 in adownward direction. In order to accommodate the vertical extension ofthe ICs 104 away from the bottom of the printed circuit board 94, thebottom of the recess 92 additionally comprises one or more hollowcavities 106 a, 106 b, 106 c which are shaped and positioned to receivethe ICs 104. Thus, when the printed circuit board 104 is installed inthe recess 92, the tapped holes 98 are aligned with screw holes 108 inthe printed circuit board 94, the probe receptacle 98 is aligned with acentral aperture 110 in the printed circuit board 94, and the ICs 104are aligned with the hollow cavities 106 a, 106 b, 106 c respectively.The bottom surface 112 of the printed circuit board 94 thus rests flaton the bottom of the recess 92, with the top surface 114 of the printedcircuit board 94 preferably below the level of the top surface 90 of thehex-nut portion of the stud 14 body. FIG. 5B illustrates the bottom side112 of the printed circuit board, showing six ICs extending up from theboard. It will be appreciated that the number of ICs provided will varywith the application and the amount of memory desired for the vibrationcoupling stud. For example, one advantageous embodiment includes onetemperature sensor IC and one memory IC.

[0069] Referring now to FIG. 9A, the printed circuit board 94 is furtherconfigured to electrically interface with the handheld vibration monitor20 by including a trace 120 on its upper surface 114 which is notcovered in solder mask, but instead comprises a bare metal contactpoint. If desired for corrosion resistance, the bare trace 120 may becoated with solder or be gold plated. In some advantageous embodiments,the trace 120 forms a ring around the central aperture 110. The trace isfurther electrically coupled to the signal pin of each IC 104 mounted tothe printed circuit board 94.

[0070] As is shown in FIG. 9B, the bottom surface 112 of the printedcircuit board 94 comprises a ground plane 122 which is electricallycoupled to additional bare traces 124 surrounding the screw holes 108 inthe printed circuit board 94. Also electrically coupled to the groundplane are the ground pins of each IC 104. When the printed circuit board94 is installed in the recess 92 of the stud 14, the stud body makeselectrical contact with the ground plane 122, and thus with the groundpins of the ICs 104.

[0071] The construction of the stud 14 is further illustrated in FIGS.10 through 12. In FIG. 10, a top view shows the printed circuit board 94mounted within the recess 92. FIG. 10 best illustrates the advantageousshape of the central aperture 110 in one embodiment of the stud 14. Inthis embodiment, the central aperture has an oblong shape conforming tothe probe 23 cross section such that the probe flat sides 17, 18 (shownin FIGS. 1 and 2) must be aligned with those sides of the probereceptacle 96 which include the threads 97. After insertion of the probe23 through the aperture 110, {fraction (1/4)} turn rotation forces thethreads to engage so as to couple the probe 23 with the stud 14.

[0072]FIG. 11 illustrates a cutaway view along line 11-11 of FIG. 10,illustrating two of the screw holes 98 and the probe receptacle 96formed inside the stud body. The bottom of the probe receptacle 96 mayinclude a central depression 124 for accepting the tip of the probe 23when the probe 23 is installed inside the stud 14, as will be describedwith reference to FIG. 13. FIG. 12 is a cutaway view along lines 12-12of FIG. 10, and illustrates a cross section of hollow cavity 106 a withthe ICs suspended from the printed circuit board 94 above the cavity 106a. Although not illustrated in FIG. 12, when one of the ICs is atemperature sensor, the body of that IC may be placed in direct contactwith the body of the stud 14, or the temperature sensor IC may fitsnugly within a specially designed cavity filled with heat conductinggrease or epoxy compound.

[0073]FIG. 13 shows the handheld vibration monitor 20 with its probeportion 23 inserted through the aperture 110 in the printed circuitboard 94 and into the probe receptacle 96 and after the {fraction (1/4)}turn rotation which engaged the threads. The probe receptacle 96 ismachined to a depth which makes the tip of the probe 23 press firmlyagainst the base of the depression 124 when the probe threads 25, 27 areengaged to the probe receptacle threads 97. Therefore, when the probe 23is rotated by {fraction (1/4)} turn after installation, threadengagement presses the tip of the probe 23 firmly into the depression124 to produce a consistent and solid mechanical contact between theprobe 23 and the stud body. It is advantageous for the interface betweenthe handheld vibration monitor 20 and the stud 14 to remain in placewith the user's hand removed from the monitor housing 21. Thisfacilitates consistency over the course of many applications of themonitor 20 to the measuring point over the life of the machine.

[0074] In FIGS. 14A and 14B, an alternative stud 14 embodiment isillustrated which is adapted to engage the probe 23 a of FIGS. 6A and6B. In this configuration, the stud 14 forms a plug which engages to thereceptacle 47 of the probe 23 a. The stud 14 comprises an approximatelycentrally located cavity 106 d, which has an upper ledge 116 forreceiving a printer circuit board 126. The printed circuit board 126 hasone or more memory or other ICs 118 as described in detail above mountedto one side so as to extend into the cavity 116 when the printed circuitboard 126 rests on the ledge. The ICs may be surface mounted to theboard, and the IC/printed circuit board assembly may be held in place byplacing epoxy into the cavity 106 d, embedding the IC into the epoxy,and letting the epoxy set. In a manner analogous to that shown anddescribed with respect to the probe 23 of FIGS. 1-2, this stud 14embodiment may comprise double start threads 128 and opposed flatsurfaces 132 so as to engage the probe 23 a of FIGS. 6A and 6B with{fraction (1/4)} turn. It will be appreciated by those in the art thatthe stud may incorporate multiple start thread configurations other thanthe double start thread embodiment illustrated. These other multiplestart thread configurations can allow probe 23 application to the stud14 in more alternative orientations than the two orientations allowed inthe specific double start embodiment illustrated. To form the electricalcommunication between the probe 23 a of FIGS. 6A and 6B, the signalterminal of the ICs is connected to a pad or trace 133 (through a via ifthe ICs are surface mounted) on the outward facing surface of theprinted circuit board 126. Also, the ground terminal of the ICs may beconnected to a trace which is routed near the edge of the printedcircuit board 126 so as to contact the ledge 116 of the stud 14, and tothereby connect the ground terminals of the ICs to the metal stud 14body.

[0075] A further advantageous stud embodiment is illustrated in FIGS.15, 16A and 16B. This embodiment is designed to couple to the vibrationmonitor interface illustrated in FIGS. 7A and 7B. The stud embodimentillustrated in these Figures has some similarities to the embodimentillustrated in FIGS. 14A and 14B. In both of these embodiments, the studforms a plug (or male end) which mates to a receptacle (or female end)on the vibration monitor. In addition, in both of these embodiments, anelectronic circuit which may include a memory and/or digital temperatureelements in the stud is subtantially surrounded by components of thestud structure.

[0076] Referring now to FIG. 15, the stud comprises a first body portion140 which includes a vibration monitor coupling point 142. As is alsodescribed above with respect to other stud embodiments, the vibrationmonitor coupling point 142 advantageously comprises flats and doublestart threads for {fraction (1/4)} turn connection between the vibrationmonitor and the stud. As described above, other multiple start threadconfigurations may alternatively be provided. The first body portion 140also includes a recess or cavity 144 (hidden from view in FIG. 15) onone end, and a hole 146 which extends from the top of the vibrationmonitoring attachment point 142 to the recess 144.

[0077] An insulating sleeve 150 is mounted within this hole 146. Theinsulating sleeve 150 may be slid up through the hole 146 via the recess144 in the end of the first body portion until a flange 152 on thesleeve 150 abuts the bottom of the recess 144. The insulating sleeve 150itself includes a central throughbore 155, in which a threadedelectrical contact 154 may be mounted. The electrical contact 154 issized such that one end 156 extends slightly past the top of theinsulating sleeve 150, while the other end 158 extends slightly beyondthe bottom of the flange 152. Thus, the electrical contact 154 isisolated from the first body portion 140 by the sleeve 150, and has oneend 158 accessible for contact with an electronic circuit element 160which may comprise a memory, a digital temperature device, etc., asdescribed below. The electronic circuit element 160 may be loaded intothe recess 144 after the sleeve 150 and contact 154.

[0078] The circuit element 160 is advantageously of a “can”configuration having a single data input/output terminal and a groundterminal. This physical configuration is common for small batteries forexample, and is also available commercially for memory and digitaltemperature elements from, for example, Dallas Semiconductor. In thisconfiguration, a data input/output terminal 162 is located at a topsurface of the device 160. Furthermore, the bottom and sides of thedevice form a common or ground terminal 164. Electrical isolation isprovided by sizing and mounting the data input/output terminal 162 suchthat it does not contact the side or bottom surfaces of the device. Thecircuit element 160 may include one or both memory storage andtemperature sensing capabilities or may have any combination ofcapabilities as described above in conjunction with FIG. 8.

[0079] After the circuit element 160 is loaded into the recess 144, itmay be clamped in place by a second stud body portion 170 which isengageable with the first body portion 144. The second body portion maycomprise a machine attachment point 172. The engagement may be made bymany different methods including friction, detents, etc. In oneembodiment, the recess 144 is internally threaded, and the second bodyportion 170 is provided with external threads 172 for threadablyengaging the first body portion 140. In this embodiment, the second bodyportion 170 may include opposed flats 176 for engagement with a wrench.When the first body portion 140 and the second body portion 170 areengaged, a flat surface 180 on the second body portion advantageouslypresses against the ground terminal 164 of the circuit element 160, andforces the data input/output terminal 162 against the end 158 of theelectrical contact 154. Thus, the data input/output terminal 162 of thecircuit element 160 is available for data transfer outside the studbody, and the ground terminal 164 of the circuit element 160 iselectrically coupled to the stud body portions 140, 170, which willgenerally be made of metal.

[0080]FIGS. 16A and 16B illustrate the stud of FIG. 15 after assembly.The cross section of FIG. 16A illustrates the second body portion 170contacting the bottom of the circuit element 160 and the top of thecircuit element 160 (which comprises the data input/output terminal 162)contacting the electrical contact 154, which is mounted inside theinsulating sleeve 150. Also illustrated in FIG. 16A is a cross sectionof the electrical contact 154. As illustrated in this Figure, thecontact 154 may advantageously comprise a hollow housing 182 with aspring 184 mounted inside. The spring 184 presses against a plunger 186which is received by the hollow housing 182. As will be explained inmore detail with reference to FIG. 17, the plunger provides a resilientelectrical connection between the stud and the vibration monitor. Forimproved electrical contact between the contact 154, the circuit element160, and the vibration monitor, the contact housing 182 and plunger 186may be plated with gold, rhodium, gold/rhodium alloy, or other highconductivity metal coating.

[0081] It will be appreciated that the stud embodiment illustrated inFIGS. 15, 16A, and 16B includes many desirable features. In addition toinexpensive manufacture, the design allows replacement and upgrades ofthe circuit element 160 to be performed by users themselves, eliminatingthe need to dispose of an entire stud when additional memory, newfeatures, etc. are desired or when there are malfunctions in the circuitelement 160.

[0082]FIG. 17 illustrates the vibration monitor probe receptacle 23 a ofFIGS. 7A and 7B coupled to the vibration monitor coupling point 142 ofthe stud embodiment of FIGS. 15, 16A and 16B. In analogy to the otherembodiments described above, engagement is initiated with a {fraction(1/4)} turn of the vibration monitor. This presses the plunger 186against the contact 65, and compresses the spring 184 to provide aneffective electrical contact between the two elements for data transferbetween the circuit element 160 and the vibration monitor.

[0083] In some embodiments of the present invention, therefore, theformation of a mechanical connection between the probe 23 or 23 a tipand the stud 14, an electrical contact is also formed between the probe23 or 23 a and the metal stud body. Furthermore, an additionalelectrical contact 58, 59, 51, 65 creates an electrical connection withthe bare trace, pad, or other electrical contact 120, 133, 186 mountedon the stud. In this way, the circuit common 53, and the second signallead 62 inside the handheld vibration monitor 20 are connected to theground and the signal terminals of the ICs, thus forming a datacommunication link between the ICs and the processing circuitry insidethe handheld vibration monitor 20.

[0084] Once this electrical and mechanical communication is established,the user can perform a wide variety of data acquisition and data storagefunctions. A flow chart illustrating one possible sequence for dataacquisition and storage is presented in FIG. 18. The first step to datacollection, shown at 190 in FIG. 18, is applying the probe 23 or 23 a tothe stud 14 and rotating the monitor 20 by {fraction (1/4)} turn toengage the threads on the probe with the threads on the stud. Asdiscussed above, this engagement also creates a connection between thevibration monitor 20 and a pad or trace on the surface of a printedwiring board mounted on the stud. At step 194, one of the two “TAKEDATA” keys discussed above is pressed. It may be noted that some studembodiments may be temporarily magnetically coupled to the machine beingmonitored rather than permanently mounted. These magnetic studs willgenerally not include memory storage for data regarding one particularmeasuring point, because they will be used at many different measuringpoints. However, a magnetically coupled stud may still advantageouslyinclude a temperature sensor with an analog electrical output indicativeof temperature. The circuitry in the handheld vibration monitor 20 istherefore preferably configured to automatically sense the presence orabsence of memory ICs. Thus, at step 196, circuitry in the handheldvibration monitor 20 checks for communication with embedded memorydevices to determine if the stud being used is a permanently mountedconfiguration having a memory for storing information relevant to themeasuring point. If no memory devices are sensed, at step 198 thehandheld vibration monitor 20 looks for an electrical signal from ananalog temperature sensing device. If no analog temperature signal issensed, at step 200 the analog temperature sensing circuitry isdeactivated, and at step 202 the analog signal from the vibrationtransducer 52 is monitored. Alternatively, if an analog temperaturesignal is detected, the monitor 20 determines the temperature at themeasuring point at step 201.

[0085] The circuitry inside the vibration monitor 20 then analyzes thesignal output from the transducer 52 at step 202. In some embodiments,an automatic settling routine is run during vibration data collection.This ensures that the vibration signal is stable before it is comparedto alarm limits or displayed on the display 26 of the monitor 20. In oneautomatic settling routine, the rate of change of the RMS signal outputfrom the transducer 52 is monitored by comparing RMS values taken atregular intervals. If the difference between successive RMS values isless than some pre-determined fraction of the latest RMS value measured,the reading is considered valid, and is made available for furtherprocessing and display. Of course, other signal analysis techniques todetermine whether or not the signal being received is settled and is notfluctuating excessively due to a poor contact or other problem will beapparent to those of skill in the art, and the specific method used mayvary widely while providing the useful “signal OK” determination. It isbeneficial, however, to include this initial signal monitoring whichrequires no user action or judgement to determine if the incoming signalappears to be a valid measurement.

[0086] After determining that the signal has the characteristics of avalid, stable signal, the signal is processed to produce velocity dataor more complex vibration signal parameters. One or more of these valuesmay then be compared to alarm limits for the measured parameters.Typically, the handheld vibration monitor 20 has default alarm limitsstored in the internal memory 74. Preferably, however, these defaultvalues may be overridden by point specific alarm limits uploaded fromthe memory chips 104 in the stud 14 as will also be described below. Atsteps 204 and 206, the measured value and any required alarms may thenbe displayed on the handheld vibration monitor 20. Alternatively, if anRS-232 communication to a palm-top processor 22 is present, data mayalso be downloaded to the processor 22 at step 208. The processor 22 maythen perform additional analysis, and may also display data and presentnecessary alarm to the user at steps 210 and 212.

[0087] At step 214, if a stud containing memory IC's is present, thehandheld vibration monitor 20 will upload the data which is available.This data may include a unique or quasi-unique point identification codeto specifically identify the point in the facility the monitor 20 isconnected to. It may also include point specific alarm levels forvibration parameters such as acceleration or velocity as well as alarmlimits for more complex frequency and amplitude analyses of thevibration spectrum. Other types of data may also be stored in the studIC memory such as bearing part or model number, factory measured bearingquality characteristics, lubrication data, when the bearing wasinstalled, appropriate measurement setup such as filtering parameters, alist of vibrational frequencies indicative of bearing defects,rotational speed, as well as others.

[0088] In some embodiments, the memory in the stud stores an assetidentification code. The asset identification code is a unique orquasi-unique code that identifies the machine or other industrial assetthat the stud is coupled to. This may be contrasted with the abovedescribed point identification code which identifies the specific stud,rather than the asset the stud is attached to. Thus, a single turbine,for example, may have several studs attached, each of which has storedin it a different point identification code and a common assetidentification code.

[0089] As bearing housing temperature is an important parameter inaddition to the various forms of vibration data, the stud 14 may includean integral digital temperature sensor IC as set forth above, andtherefore digital temperature data may also be retrieved at step 214. Aswill also be described below, the data stored in the stud mayadditionally comprise prior time and date stamped vibration andtemperature measurements made at that measuring point.

[0090] If no data has been stored in the stud, and no temperature datais available, the circuitry inside the vibration monitor 20 then waitsfor a stable signal output from the transducer 52 at step 216 as hasbeen described with reference to step 202. After the measurement hasbeen made, the measurement is stored at step 218 in the stud 14 by themonitor 20 over the electrical interface to the ICs. In someadvantageous embodiments, the measurement is stored in association withthe date and perhaps also the time that the measurement was taken. Whenno prior data is stored in the stud, this initial measurement ispreferably tagged as a baseline measurement, which is used to comparewith future measurements to evaluate the presence of defects and otheralarm conditions which are revealed by changes from the baselinemeasurement. Then, the monitor moves to the data and alarm display steps204, 206, 210, 212 discussed above.

[0091] Depending on whether or not the monitor 20 is interfacing with apalm-top processing unit 22, any data retrieved from the stud at step214 is used to configure either the monitor alone at step 220 or boththe monitor 20 and palm-top processor 22 at step 222 for display andalarm parameters which are appropriate to the measuring point. At step224, if a series of prior measurements are stored in the stud 14, themonitor or palm-top processor evaluates the trend around or away fromthe baseline measurement initially taken and stored in the stud usingprocedures for vibration data analysis which are well known in the art.Following this retrieval and analysis of prior data, the monitor 20analyzes the transducer signal at step 226, waiting for a valid readingas described above with reference to steps 202 and 216. At step 228, thelatest measurement taken at step 226 is stored in the stud IC memory. Insome advantageous embodiments, a first-in, first-out (FIFO) series ofdata points are stored in the stud. Once the FIFO stack is full, newentries force the oldest entry out. However, the entry tagged as thebaseline entry will be retained. Storing such a historical record ofmeasurements in the stud itself can be useful in watching trends overtime in the measured parameters. When the prior measurements are storedin the stud 14, a significant or dangerous difference between thecurrent measurement and past measurements can be spotted immediately,without requiring the value to be first downloaded to a host computerwhich stores the past measurement data. In some embodiments, thedecision of whether or not to store the measured data in the stud ismade by the user, while in other alternative embodiments, the handheldvibration monitor 20 automatically stores the measured value in the stud14 memory without additional user interaction. At step 230 then, the newmeasurement and stored trend are evaluated for the generation of alarmsto the user, and the system enters the data and alarm display steps204,206,210,212.

[0092] It is generally advantageous to store at least the date themeasurement was taken in association with the measurement itself. It canbe appreciated that this information would often be useful in evaluatingthe significance of changes in vibration measurements at different dataacquisition times. In some embodiments, only one measurement per daywill be stored, and any further measurements taken on that day willoverwrite the previously made measurement. This allows a user toconveniently overwrite a previous entry if the user suspects that baddata was gathered at that point earlier in the day. After theseoperations are complete, the user removes the probe.

[0093] It may also be desirable to add or alter bearing parameters,alarm limits, and other information stored or storable in the memory ofthe vibration coupling stud 14. In many advantageous embodiments of thepresent invention, the creation or revision of alarm limits, severitymatrices, configuration data, etc. stored in the stud at the measuringpoint is tightly controlled by a host computer system. In advantageousembodiments, the host system will interface with the palm-top processor22 and download any new alarm limits, or other new or revised data to bestored in the stud 14. The host system may also instruct the monitor 20to store the new parameters in the stud 14 during the next monitor/studconnection. This writing process may be contrasted with the process ofstoring date stamped vibration measurements in the stud 14, whichpreferably can be accomplished with the monitor 20 alone, without anymonitor 20 interface to the palm-top processor 22 or host systemintervention.

[0094] The vibration monitoring system of the present invention thusprovides several advantages over prior art vibration monitoring systems.A wide variety of information about the machine, bearing, or otherdevice being monitored can be stored in the vibration coupling stud.This information is easily retrievable and alterable during routinevibration data acquisition. Temperature data may also be retrieved fromthe stud itself. The handheld vibration monitor is configured to promotea consistent mechanical coupling and stable output reading with eachapplication of the monitor to a measuring point. In addition, thehandheld vibration monitor may download various forms of vibration datain a digital format which is consistent with industry standardcommunication protocols and hardware. This allows standard, commerciallyavailable palm-top computers to be used with the handheld vibrationmonitor. Thus, users need only run appropriate software on palm-topsthey already own or choose themselves, and do not need separatelyacquire palm-top computers having hardware dedicated to interfacing withthe handheld vibration monitor.

[0095] The foregoing description details certain preferred embodimentsof the present invention and describes the best mode contemplated. Itwill be appreciated, however, that no matter how detailed the foregoingappears in text, the invention can be practiced in many ways. As is alsostated above, it should be noted that the use of particular terminologywhen describing certain features or aspects of the present inventionshould not be taken to imply that the broadest reasonable meaning ofsuch terminology is not intended, or that the terminology is beingre-defined herein to be restricted to including any specificcharacteristics of the features or aspects of the invention with whichthat terminology is associated. The scope of the present inventionshould therefore be construed in accordance with the appended claims andany equivalents thereof.

What is claimed is:
 1. A stud for coupling machine vibrations to atransducer comprising: a body having a machine attachment portion forattaching said stud to a point on a machine one or more memories mountedon said stud, wherein said memories store one or more types of dataselected from the group consisting of asset identification code, alarmlimits, bearing part number, bearing quality characteristics,lubrication information, installation date, signal filtering parameters,defect indication frequency, and date stamped value of a parametermeasured during a previous data collection operation.
 2. The vibrationcoupling stud of claim 1, wherein said stud comprises a body having aninternal recess, said recess containing said one or more memories suchthat said body substantially surrounds said one or more memories.
 3. Thevibration coupling stud of claim 2, wherein said body comprises anelectrically conductive portion and an insulating portion, wherein saidelectrically conductive portion and said insulating portions togethersubstantially surround said one or more memories, and wherein saidinsulating portion is provided between an input/output terminal of saidone or more memories and said electrically conductive portion of saidbody so as to isolate said data input/output terminal from saidelectrically conductive portion.
 4. The vibration coupling stud of claim2, wherein said stud comprises first and second engageable portionswhich clamp said one or more memories in said recess when said portionsare engaged.
 5. The vibration coupling stud of claim 4, wherein saidfirst engageable portion comprises a vibration monitor coupling point,and wherein said second engageable portion comprises said machineattachment portion.
 6. The vibration coupling stud of claim 5, whereinsaid vibration monitor coupling point comprises multiple start threads.7. The vibration coupling stud of claim 6, wherein said first and secondengageable portions are threadably engaged.
 8. The vibration couplingstud of claim 6, wherein said one or more memories comprise ainput/output terminal and a ground terminal.
 9. The vibration couplingstud of claim 8, additionally comprising an electrical contact havingone end in contact with said input/output terminal and another endextending through said first engageable portion.
 10. The vibrationcoupling stud of claim 9, wherein said second engageable portion is incontact with said ground terminal.
 11. The vibration coupling stud ofclaim 10, wherein said first engageable portion comprises a vibrationmonitor coupling point, and wherein said second engageable portioncomprises said machine attachment portion.
 12. A vibration monitoringsystem comprising: a stud comprising a machine connection point and avibration monitor connection point; a vibration monitor comprising acoupler for removably coupling to said stud at said vibration monitorconnection point so as to detect machine vibration through said stud,said portable vibration monitor further comprising processing circuitryincluding a first memory circuit, wherein said first memory circuitstores one or more types of data selected from the group consisting ofalarm limits, point identification data, date, time, and bearing data,and wherein said processing circuitry is connected to an electricalinterface associated with said coupler; a second memory circuit mountedto said stud, wherein said second memory circuit stores one or moretypes of data selected from the group consisting of an assetidentification code, alarm limits, bearing part number, bearing qualitycharacteristics, lubrication information, installation date, signalfiltering parameters, defect indication frequency, and date stampedvalue of a parameter measured during a previous data collectionoperation, and wherein said second memory circuit is connected to anelectrical interface associated with said vibration monitor connectionpoint, whereby data stored in said vibration monitor is transferred fromsaid vibration monitor to said stud and data stored in said stud istransferred from said stud to said vibration monitor through saidelectrical interfaces.
 13. The vibration monitoring system of claim 12,wherein said second memory circuit is mounted to a printed circuit boardmounted on said stud.
 14. The vibration monitoring system of claim 12,wherein said second memory circuit comprises an EEPROM.